The usual free delivery with Hexus or AV Forums otherwise it's £86.29 delivered.
This contains a Samsung HM500LI Hard drive (confirmed by several people). This is cheaper than the bare drive which is £91.61 normally (or £88.11 today on the today only page) and you also get an enclosure. The Samsung is 9.5mm and therefore PS3 compatible.
HUKD member spraint has confirmed that the enclosure cannot accommodate a larger 12.5mm drive, and as the Samsung is the only 9.5mm 500GB drive at the moment, it seems likely that LaCie will continue to use these drives unless they decide to change the size of the enclosure in the future.
The Samsung bare drive has its own 3 year warranty with Samsung. So you can open the enclosure and not have to worry about destroying it or invalidating the Lacie warranty (instructions kindly provided by spraint below).
Found here http://forums.hexus.net/current-bargains/152607-samsung-hm500li-spinpoint-m6-2-5-sata-only-78-a.html